The cyst mass arised inside the cheek May be due to-chronic cheek biting habit,pericoronitis
due to impacted wisdom tooth
,oral habits like tobacco or pan chewing.
As your dentist
suggested,based on biopsy report treatment can be planned.
Meanwhile,maintain oral hygiene well.
Apply mucopain gel on the affected area.
Swish with lukewarm saline or chlorhexidine
Maintain oral hygiene well.
Avoid intake of spicy foods.
Discontinue the habit of toacco or pan chewing.
Hope this helps.